1. Field of the Invention
The present invention generally relates to a process for fabricating a micro-display. More particularly, the present invention relates to a process for fabricating a micro-display with a larger micro-display aperture ratio.
2. Description of the Related Art
In recent years, liquid crystal pixel structures have been widely used in many types of liquid displays and liquid crystal projectors including such family products as the liquid crystal televisions, hand-held computers or desktop computers. In particular, liquid crystal projectors have become one of the indispensable tools for displaying something large. At the core of a liquid crystal projector is an optical engine. The optical engine mainly comprises a light source, optical elements built from sets of prisms and a number of liquid crystal panels corresponding to various optical paths (R, G and B). The aforesaid liquid crystal panels, due to consideration regarding the size of the pixel structure, mostly deploy the liquid crystal on silicon (LCOS) technology, which belongs to a kind of micro-display.
LCOS is a liquid crystal panel that builds on a silicon wafer back panel. Because the LCOS liquid crystal panel that utilizes a silicon wafer as a back panel uses metal-oxide-semiconductor (MOS) transistors instead of the conventional thin film transistors, the pixel electrodes are fabricated using metallic material. Hence, the LCOS belongs to a reflective type of liquid crystal panel. Because the metallic pixel electrode of LCOS completely covers a pixel region, especially, completely covers the MOS transistors, the image display capacity of the LCOS panel is much better than a conventional liquid crystal display. Moreover, with the LCOS build on a silicon back panel, the LCOS occupies a small volume and has a high resolution. Therefore, it is quite common to see the application of LCOS technology inside a liquid crystal projector. Furthermore, the LCOS technology also matches the demand for producing less bulky liquid crystal projectors.
For a micro-display, a higher the aperture ratio usually implies a better light reflection capacity and a higher display performance. However, most micro-display devices using LCOS as the liquid crystal panel has a moderate aperture ratio and device performance due to the limitations in the photolithographic process. Thus, increasing the aperture ratio and improving device performance have become the two most important directions in the future development of micro-display devices.